NEW YORK (CNNMoney.com) -- The odds of Republicans controlling the next Congress have dropped sharply since news of the Congressional-page scandal broke, according to a "futures" market operated by the University of Iowa.

The Iowa Electronic Market, which offers contracts on the outcomes of political and economic events, says the percentage of investors in the 2006 Congressional Control market believing Republicans will hold full control of Congress has dropped to 39 percent from 58.5 percent on Sept. 28, when news was revealed about Rep. Mark Foley's correspondence with pages.

Those believing the Democrats will take full control of Congress have risen to 22.9 percent from 11.2 percent Sept. 29, the day the Florida Republican resigned.

"The best guess coming from the market is that it will be a divided Congress," says Prof. Forrest Nelson of the University of Iowa Tippie College of Business, which has operated the markets since since 1988.

The percentage banking on the Democrats taking control of House while the Republicans maintain control of the Senate has risen to 36 percent from 28.4 percent.

"Traders are betting Republicans will continue to hold the Senate but the House is really up for grabs," said Nelson.

Economics students, professors and political experts make small investments in futures based on the outcomes of political events. The Iowa Electronic Market is designed as an educational project rather than a lucrative project.

The minimum bet is $5. The maximum for any investor is $500.

Nelson says a "sure thing" would have to score 90 percent of the market or more.

Ireland-based Tradesports.com bettors gave a GOP-controlled Senate a 69.6 percent chance of occurring Wednesday, with 100 percent being a certainty.

However, bettors on the online service wagered a GOP-controlled House has only a 39.3 percent of happening.

"The chances of the Democrats taking control of the House look really good today - though, of course that could change in the next 27 days," said Josh Kurtz, politics editor at Roll Call, which covers Congressional news.

"The Democrats' path to taking over the Senate is a little more difficult, but not impossible by any means," he added.